This disclosure relates to a bushing for a variable vane assembly. More particularly, the disclosure relates to a bushing for an inner diameter of a variable vane that retains the vane and minimizes wear.
A gas turbine engine typically includes a compressor section, a combustor section and a turbine section. Air entering the compressor section is compressed and delivered into the combustion section where it is mixed with fuel and ignited to generate a high-speed exhaust gas flow. The high-speed exhaust gas flow expands through the turbine section to drive the compressor and a ground-based generator for industrial gas turbine engine applications. The compressor and turbine sections include a plurality of rotating blades and vanes spaced between the rows of blades. The vanes serve to direct and control the flow of air through the rows of blades.
One type of vane is a variable vane. In a variable vane, a vane pivots relative to a radial axis taken from a central axis of the engine. An actuator rotates a first side of the vane to pivot and a second opposed side of the vane is supported for rotation in a shroud. Typically, the actuator is at a radially outer location. In the event of a variable inlet vane failure, the rotated and supported sides of the vane may become disconnected from one another. The supported side of the vane may become liberated from the shroud and may be ingested by the rotating fan or other downstream rotating engine components. The supported side of the vane may include a retention feature to allow it to be retained in the shroud.
The supported side of the vane generally includes a bushing to facilitate rotation in the shroud. In some current designs, the bushing may be split to allow for the incorporation of a retention feature, reducing the contact area between the bushing and the supported side of the vane and the shroud. Additionally, material selection for bushings is typically limited due to the high-wear conditions in which they operate and the necessity for material matching with the supported side of the vane.